As of yesterday, IMAP/SMTP access disabled for existing free accounts. Another one bites the dust...

Code:

An update on the IMAP service
Dear users, we received quite a lot of messages of users that were concerned regarding the IMAP support removal for free accounts.
The reason for this limitation is the cost of offering this protocol. In fact, due to the nature of the protocol, great loads are experienced
from our side. Sadly managing all this load for free is hardly sustainable.
However, we may not have made this change as smooth as it should have been and clearly have not anticipated the concerns users
are currently manifesting and we are sincerely sorry for that, we really didn't thought wrong and the intention absolutely wasn't forcing
users into buying our pro plan.
For this reason, users that used the service before this change (04/08/2017) will be offered a pro account for a period of one month.
You can configure IMAP on your account here.
If you have any more questions or concerns, you can reach us through our contact form

...well for me openmailbox.org is dead. i do not believe that they will not force people to buying the proplan.